Change the flag set to specify bulk delete and expand archives from a HTTP
header to a query parameter.

This is needed because query parameters show up in proxy logs and headers do
not. With this change it will be easy to determine from any log line that gets
created from the original request (of which there is currently none) that the
request was a bulk action.

Note: This is not backwards compatible with the previous method of setting a
header. Because the bulk middleware has not been included in an openstack swift
release this should be fine.

Change-Id: I0297fa2de9e491bf0b8c430c0781e2e12316ed4b
Merge "Change the flag set to specify bulk delete and expand archives from a HTTP header to a query parameter."